The relationship between chronic pelvic pain, uterine contractility, and the chemical messengers that regulate uterine contractions and pain are not well understood. This research proposal is designed to test the hypothesis that the endocannabinoids, arachidonoylethanolamide (anandamide; AEA), 2-arachidonoyl glycerol (2-AG) and the putative lipid mediator N-arachidonoylglycine (NAGly) play a functional role in uterine contractions and pain and that this regulation is controlled by the hormonal milieu. Specific aim 1 is designed to measure endogenous levels of AEA, 2-AG, and NAGly, changes in cannabinoid receptor density and affinity, and FAAH activity in the rat reproductive tract as a function of changes in the hormonal milieu. Specific aim 2 is designed to measure the effect of AEA, 2-AG, and NAGly on uterine contraction rates and amplitudes. Specific aim 3 is designed to measure the effects of AEA, 2-AG, and NAGly on behavioral responses to noxious uterine stimulation. Preliminary data in this proposal demonstrates that uterine levels of AEA, 2-AG, and NAGly are regulated by the hormonal milieu and that this change may facilitate changes in uterine contractions. The experiments in this proposal will provide information that could lead to a novel platform from which to launch new studies in the etiology and treatment of chronic pelvic pain in women.